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>Video for Linux Two API Specification: Revision 0.24</TH
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>V4L2_PIX_FMT_YVU420 ('YV12'), V4L2_PIX_FMT_YUV420 ('YU12')</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN4854"
></A
><H2
>Name</H2
><CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_YVU420</CODE
>, <CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_YUV420</CODE
>&nbsp;--&nbsp;Planar formats with &frac12; horizontal and
vertical chroma resolution, also known as YUV 4:2:0</DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN4860"
></A
><H2
>Description</H2
><P
>These are planar formats, as opposed to a packed format.
The three components are separated into three sub- images or planes.
The Y plane is first. The Y plane has one byte per pixel. For
<CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_YVU420</CODE
>, the Cr plane immediately
follows the Y plane in memory. The Cr plane is half the width and half
the height of the Y plane (and of the image). Each Cr belongs to four
pixels, a two-by-two square of the image. For example,
Cr<SUB
>0</SUB
> belongs to Y'<SUB
>00</SUB
>,
Y'<SUB
>01</SUB
>, Y'<SUB
>10</SUB
>, and
Y'<SUB
>11</SUB
>. Following the Cr plane is the Cb plane,
just like the Cr plane. <CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_YUV420</CODE
> is
the same except the Cb plane comes first, then the Cr plane.</P
><P
>If the Y plane has pad bytes after each row, then the Cr
and Cb planes have half as many pad bytes after their rows. In other
words, two Cx rows (including padding) is exactly as long as one Y row
(including padding).</P
><DIV
CLASS="EXAMPLE"
><A
NAME="AEN4871"
></A
><P
><B
>Example 2-1. <CODE
CLASS="CONSTANT"
>V4L2_PIX_FMT_YVU420</CODE
> 4 &times; 4
pixel image</B
></P
><DIV
CLASS="FORMALPARA"
><P
><B
>Byte Order. </B
>Each cell is one byte.
                <DIV
CLASS="INFORMALTABLE"
><P
></P
><A
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></A
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FRAME="void"
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><COL
WIDTH="2*"
ALIGN="LEFT"><COL><COL><COL><COL><TBODY
VALIGN="TOP"
><TR
><TD
>start&nbsp;+&nbsp;0:</TD
><TD
>Y'<SUB
>00</SUB
></TD
><TD
>Y'<SUB
>01</SUB
></TD
><TD
>Y'<SUB
>02</SUB
></TD
><TD
>Y'<SUB
>03</SUB
></TD
></TR
><TR
><TD
>start&nbsp;+&nbsp;4:</TD
><TD
>Y'<SUB
>10</SUB
></TD
><TD
>Y'<SUB
>11</SUB
></TD
><TD
>Y'<SUB
>12</SUB
></TD
><TD
>Y'<SUB
>13</SUB
></TD
></TR
><TR
><TD
>start&nbsp;+&nbsp;8:</TD
><TD
>Y'<SUB
>20</SUB
></TD
><TD
>Y'<SUB
>21</SUB
></TD
><TD
>Y'<SUB
>22</SUB
></TD
><TD
>Y'<SUB
>23</SUB
></TD
></TR
><TR
><TD
>start&nbsp;+&nbsp;12:</TD
><TD
>Y'<SUB
>30</SUB
></TD
><TD
>Y'<SUB
>31</SUB
></TD
><TD
>Y'<SUB
>32</SUB
></TD
><TD
>Y'<SUB
>33</SUB
></TD
></TR
><TR
><TD
>start&nbsp;+&nbsp;16:</TD
><TD
>Cr<SUB
>00</SUB
></TD
><TD
>Cr<SUB
>01</SUB
></TD
><TD
>&nbsp;</TD
><TD
>&nbsp;</TD
></TR
><TR
><TD
>start&nbsp;+&nbsp;18:</TD
><TD
>Cr<SUB
>10</SUB
></TD
><TD
>Cr<SUB
>11</SUB
></TD
><TD
>&nbsp;</TD
><TD
>&nbsp;</TD
></TR
><TR
><TD
>start&nbsp;+&nbsp;20:</TD
><TD
>Cb<SUB
>00</SUB
></TD
><TD
>Cb<SUB
>01</SUB
></TD
><TD
>&nbsp;</TD
><TD
>&nbsp;</TD
></TR
><TR
><TD
>start&nbsp;+&nbsp;22:</TD
><TD
>Cb<SUB
>10</SUB
></TD
><TD
>Cb<SUB
>11</SUB
></TD
><TD
>&nbsp;</TD
><TD
>&nbsp;</TD
></TR
></TBODY
></TABLE
><P
></P
></DIV
>
              </P
></DIV
><DIV
CLASS="FORMALPARA"
><P
><B
>Color Sample Location. </B
>                <DIV
CLASS="INFORMALTABLE"
><P
></P
><A
NAME="AEN4948"
></A
><TABLE
BORDER="0"
FRAME="void"
CLASS="CALSTABLE"
><COL><COL><COL><COL><COL><COL><COL><TBODY
VALIGN="TOP"
><TR
><TD
>&nbsp;</TD
><TD
>0</TD
><TD
>&nbsp;</TD
><TD
>1</TD
><TD
>&nbsp;</TD
><TD
>2</TD
><TD
>&nbsp;</TD
><TD
>3</TD
></TR
><TR
><TD
>0</TD
><TD
>Y</TD
><TD
>&nbsp;</TD
><TD
>Y</TD
><TD
>&nbsp;</TD
><TD
>Y</TD
><TD
>&nbsp;</TD
><TD
>Y</TD
></TR
><TR
><TD
>&nbsp;</TD
><TD
>&nbsp;</TD
><TD
>C</TD
><TD
>&nbsp;</TD
><TD
>&nbsp;</TD
><TD
>&nbsp;</TD
><TD
>C</TD
><TD
>&nbsp;</TD
></TR
><TR
><TD
>1</TD
><TD
>Y</TD
><TD
>&nbsp;</TD
><TD
>Y</TD
><TD
>&nbsp;</TD
><TD
>Y</TD
><TD
>&nbsp;</TD
><TD
>Y</TD
></TR
><TR
><TD
>&nbsp;</TD
><TD
>&nbsp;</TD
><TD
>&nbsp;</TD
><TD
>&nbsp;</TD
><TD
>&nbsp;</TD
><TD
>&nbsp;</TD
><TD
>&nbsp;</TD
></TR
><TR
><TD
>2</TD
><TD
>Y</TD
><TD
>&nbsp;</TD
><TD
>Y</TD
><TD
>&nbsp;</TD
><TD
>Y</TD
><TD
>&nbsp;</TD
><TD
>Y</TD
></TR
><TR
><TD
>&nbsp;</TD
><TD
>&nbsp;</TD
><TD
>C</TD
><TD
>&nbsp;</TD
><TD
>&nbsp;</TD
><TD
>&nbsp;</TD
><TD
>C</TD
><TD
>&nbsp;</TD
></TR
><TR
><TD
>3</TD
><TD
>Y</TD
><TD
>&nbsp;</TD
><TD
>Y</TD
><TD
>&nbsp;</TD
><TD
>Y</TD
><TD
>&nbsp;</TD
><TD
>Y</TD
></TR
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></TABLE
><P
></P
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